As a W-2 employee, you can claim the portion of your health
insurance premiums not paid with pre-tax dollars and not paid by a subsidy.
This will be taken as an itemized deduction on Schedule A. In addition,
if your health plan has a deductible, and you incurred out-of-pocket medical
costs that insurance (or an HSA/MSA/FSA) did not cover or reimburse you for,
then you can also claim those medical costs as an itemized deduction.
Keep in mind that an itemized deduction for medical expenses is
subject to a 10% of AGI threshold (7.5% if age 65+), which means that your
total medical expenses have to exceed 10% of your Adjusted Gross Income before
you'll begin to get the deduction. Also, you'll have to be able to
itemize (rather than take the standard deduction).
You'll enter them by following this pathway: Federal Taxes > Deductions & Credits >
Medical > Medical Expenses, and follow the prompts.
If you're self-employed, there's a special Self
Employed Health Insurance Deduction (see this link https://www.irs.gov/uac/newsroom/dont-miss-the-health-insurance-deduction-if-youre-self-employed).
If your particular state has some form of medical premium
deduction/credit, TurboTax will ask you the appropriate questions in the State
interview section.